Controlling heat transfer to workpiece in vapour phase soldering unit

摘要

The process for controlling the heat transfer to a workpiece being soldered in a vapour phase soldering unit comprises: (a) determining the height of the vapour phase in the process chamber; (b) introducing the workpiece into the upper limit area of the vapour phase; (c) holding the workpiece in the limit area; and (d) further introducing the workpiece into the vapour phase with a predetermined velocity. Also claimed are: (i) a chain transport system for transporting the workpiece through a vapour phase soldering unit comprising: (a) a first transport system for passing through a preheating zone; (b) a second transport system for passing vertically through the vapour phase of a soldering zone; and (c) a third transport system for passing through into a cooling zone. During transport, the workpiece assumes a horizontal position. The second transport system is also in thermal contact with the vapour phase at its starting and passing on positions; (ii) a transport process using the above chain transport system comprising: (a) transferring the workpiece to the first transport system; (b) passing through the preheating zone; (c) transferring the workpiece to the second transport system; (d) vertically passing through the vapour phase from a starting position downwards and then back upwards again to the exit position; (e) transferring the workpiece to the third transport system; (f) passing through the cooling zone; and (g) taking the workpiece out of the vapour phase soldering unit; (iii) a vapour phase soldering unit in which a drying unit is provided on the vapour phase, the drying unit evaporating condensed liq. from the vapour phase by means of under pressure; and (iv) the use of the vapour phase soldering unit, the processes and/or the chain transport system in combination.